Could use some guidance on rebuildinbg my 1969 428 engine

I am new to this forum. After reading some of the tech suggestions to questions from other Pontiac enthusiasts, I thought that I should seek some help before rebuilding my 428 motor. Specifically,I am looking for suggestions on camshaft selection, compression ration and head selection.

Some info about the broken engine itself. It is 1969 428, Code YH motor that came out of either a Bonneville or Catlaina, I'm not sure. I do know that it has @ 68,000 original miles on it. It has never been taken apart. It has "46" heads and a stock 4 BBL intake. The engine ran beautifully and made some nice power ....everything was fine....until....

I got a little bit carried away last summer while driving my 1970 GTO and ended up breaking a piston and ring. I have decided to rebuild the engine completely.

The new engine will be going into my 1970 GTO ragtop. The GTO has an M-20 4 speed and 3.42:1 posi rear end. I am weekend and summer cruiser who like the engine to be a wee bit beefier than stock. I am thinking @ 450HP without doing any really radical machine work or components.

I plan on using the 428 block/crank and upgrading to forged rods and pistons.

For heads, I am thinking of ditching the small valve "46" heads for a set of either casting # "12" (from a 1970 400 cid) or #"64" (from a 1970 455). I am hoping to end up with compression @ 9.5:1.

Definitely go with the 64 heads.Consider port matching intake and and heads and go with the Ram Air repro exhaust manifolds, unless you sepcifically want to go with long branch headers (which will help in the HP department)If you have the $, then I'd opt for Edelbrock aluminum D-port heads.

The Q-jet can be tuned to give you exceptional performance, but you'll need patience and a written guide as they aren't the easiest things to work on.

Given that you broke a ring and piston, chances are you'll need some cylinder work. Going .030" over w/ the 64 heads and zero decked block will give you about 9.7:1 CR which is still doable w/Iron heads. w/.020" on the deck height, instead of zero, you'll get about 9.3:1 CR. If it were me, I'd leave the deck hieght as it is and bore the block to get my CR. That way, it will give you more room for just that little bit of higher lift cam for more breathing.For the bottom end, which crank to you have? the Arma steel? or the later N (nodular iron)?Definitely have the bottom end balanced after you obtain the rods/pistons.Stay with a flat top piston.. Not necessarily forged, but the extra strength wouldn't hurt. Have the machine shop weigh the reciprocating and rotating mass and calculate safe RPM levels. You might look into verious methods of strengthening the crank shaft (shot peening, etc..).To get your 450 target @ ~9.5 CR, it's all about breathing.

the 428 lends itself to higher RPM's with the shorter stroke/bigger cylinders, but this motor can be a torque monster also.